Apparatus for the stabilization of head position

ABSTRACT

An apparatus is provided to fix a thermoplastic mask to a patient. The apparatus includes a member having a teeth-receiving portion formed to be positioned adjacent to a cranio facial bone of the patient, a fixation member coupled to the member, the fixation member including a plate and a fastener, a distinct fastener plate formed for coupling with the fastener to couple the mask to the fixation member so that the member is in a fixed position relative to the mask, and a lower plate member positioned adjacent to the member.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.10/072,778 filed on Feb. 8, 2002, which itself claims priority to U.S.Provisional Patent Application Ser. No. 60/267,536 filed Feb. 9, 2001.

TECHNICAL FIELD

The present invention relates to an apparatus for immobilizing apatient's skull during a medical diagnostic or treatment procedure, andmore particularly to an apparatus which permits precise and reproduciblepositioning of the patient's head and neck during radiation therapy orlike medical procedures.

BACKGROUND AND SUMMARY OF THE INVENTION

A variety of medical diagnostic and treatment procedures require that apatient's skull be fixed in an accurate and reproducible position. Oneexample of such a treatment procedure is radiation therapy, which isused to deliver radiation to a target, such as a tumor. An importantstep in this therapy is treatment planning. To aid in this planning,stereotactic techniques have been developed, which employ accurate andreproducible positioning of the patient's skull during radiographicstudies. See, for example, U.S. Pat. No. 5,797,924.

It is also important to immobilize the patient during treatment andradiographic examination in order to assure that radiation is deliveredexactly where it is needed and that targets and surrounding normalstructures are precisely located. A thermoplastic mask is often used toimmobilize the patient's head and ensure reproducibility of thetreatment.

According to the present invention, an apparatus is provided that isformed to fix a thermoplastic mask to a patient. The apparatus comprisesa member having a teeth-receiving portion formed to be positionedadjacent to a cranio facial bone of the patient, a fixation membercoupled to the member, the fixation member including a plate and afastener, a distinct fastener plate formed for coupling with thefastener to couple the mask to the fixation member so that the member isin a fixed position relative to the mask, and a lower plate memberpositioned adjacent to the member.

According to another embodiment of the present invention, an apparatusis provided that is formed to fix a thermoplastic mask to a patient. Theapparatus comprises a mouthpiece member, a fixation member coupled tothe mouthpiece member, the fixation member including a plate and atleast one fastener extending away from the plate, a distinct fastenerplate formed for attachment with the at least one fastener so that themask is coupled between the plate and the fastener plate, and a lowerplate member positioned adjacent to the mouthpiece member.

According to another embodiment of the present invention an assemblyformed to immobilize a patient's skull during a medical procedure isprovided. The assembly comprises a thermoplastic mask, a fixation memberincluding an attachment portion, an extension extending from theattachment portion, and a plate coupled to the extension, the mask beingformed to extend across the plate, a mouthpiece member coupled to theattachment portion of the fixation member in order that the mouthpiecemember be coupled to the thermoplastic mask, and a lower plate memberpositioned adjacent to the mouthpiece member.

These and other features of the present invention will be more fullyunderstood from the following detailed description of the inventiontaken together with the accompanying claims. It is noted that the scopeof the claims is defined by the recitations therein and not by thespecific discussion of the features set forth in the presentdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail below with reference tothe drawings, in which:

FIG. 1 is an exploded perspective view of the apparatus in accordancewith the present invention.

FIG. 2 is a top view of the assembled apparatus of FIG. 1.

FIG. 3 is a front perspective view of the apparatus of FIG. 1 coupled toa thermoplastic mask.

FIG. 4 is a rear perspective view of the apparatus of FIG. 1 coupled toa thermoplastic mask.

FIG. 5 is a view taken along lines 5-5 of FIG. 3.

FIG. 6 is an exploded perspective view an apparatus in accordance withthe present invention.

FIG. 7 is a front perspective view of the apparatus of FIG. 6 coupled toa thermoplastic mask.

FIG. 8 is a view taken along lines 8-8 of FIG. 7.

FIG. 9 is an exploded perspective view an apparatus in accordance withthe present invention.

FIG. 10 is an exploded perspective view an apparatus in accordance withthe present invention.

FIG. 11 is a rear perspective view of the apparatuses of FIGS. 1, 9, and10 coupled to a thermoplastic mask.

FIG. 12 is an exploded perspective view of an apparatus in accordancewith the present invention.

FIG. 13 is a front perspective view of the apparatuses of FIGS. 6, 10,and 12 coupled to a thermoplastic mask.

FIG. 14 is a rear perspective view of the apparatus of FIGS. 6, 10, and12 coupled to a thermoplastic mask.

FIG. 15 is a rear perspective view of an apparatus in accordance withthe present invention.

FIG. 16 is a rear perspective view of an apparatus in accordance withthe present invention.

FIG. 17 is a rear perspective view of an apparatus in accordance withthe present invention.

FIG. 18 is a top view of an assembled apparatus in accordance with thepresent invention.

FIG. 19 is a side view of the apparatus of FIG. 18.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention relates to an apparatus and method for fixing athermoplastic mask to the head of a patient during medical diagnosticand treatment procedures. The apparatus is formed to press the maskagainst rigid and fixed portions of the patient's skull in order tomaintain a rigid position of the mask relative to the patient's skull.Thus, a patient's head is prevented from moving in the mask. It isappreciated that apparatus 10, 110, 210, 310, 410, 510, 810 as discussedhereafter, may be distributed to a user as a separate apparatus, as partof a kit with a thermoplastic mask 52, or already coupled to the mask52. Various aspects of the invention are presented in FIGS. 1-19, whichare not drawn to scale and wherein like components in the several viewsare numbered alike.

FIGS. 1-4 illustrate an aspect of the invention in the form of anapparatus 10 that is formed to fix a mask to the fixed cranio facialbones, i.e. maxilla. Apparatus 10 includes a mouthpiece member 12, afixation member 14 extending from the mouthpiece member 12, a fastenerplate 16, and a spacer 18 positioned to lie between the fixation member14 and the fastener plate 16.

Mouthpiece member 12 is formed from a resinous material that softenswhen heated. A non-limiting example of a suitable material for formingmouthpiece is ELVAX® 470, an ethylene vinyl acetate copolymer andterpolymer resin, which is commercially available from E.I. DuPont deNemours, Wilmington, Del. It is appreciated, however that the mouthpiececan also be constructed of a rigid plastic or be a true custom mould, asdentists use in accordance with this disclosure. Mouthpiece member 12includes a top side 21, a bottom side 25, a front side 24, a back side26, and a teeth-receiving portion 22 extending from the top side 21between the front and back sides 24, 26. Additionally, the back side 26has a generally concave-shaped cavity 27 that is sized to receivemovement of the tongue therein. The receiving portion is defined by aninner surface 23. It is appreciated that the shape of the mouthpiece mayvary in accordance with the present disclosure.

Fixation member 14 is coupled to the front side 24 of the mouthpiecemember 12 and is formed for attachment to the fastener plate 16.Referring to FIG. 1, the fixation member 14 is generally formed from arigid plastics material and includes a first end 28 coupled tomouthpiece member 12 and a second end 30 that is formed for attachmentwith the fastener plate 16. As will be discussed hereafter, fixationmember may be formed in a variety of shapes and sizes in accordance withthe present invention. It is also appreciated that although the fixationmember 14 is illustratively formed of a rigid plastics material, itcould be constructed of a variety of materials including metal inaccordance with the present disclosure.

As shown in FIGS. 1 and 2, the first end 28 of the fixation member 14includes an attachment portion 32 that takes the general shape of themouthpiece member 12. The attachment portion 32 illustratively includesfour spaced-apart connectors 34 (FIG. 1) extending away from the firstend 28 and toward the mouthpiece member 12. In one aspect of theinvention, the connectors 34 are coupled to the mouthpiece member 12using ultrasonic welding. It is appreciated, however, that theattachment portion 32 of the fixation member 14 may be coupled to themouthpiece member 12 using any number of commercially availableadhesives or with heat welding in accordance with this disclosure.

Referring now to FIG. 2, the first end 28 of the fixation member 14includes an extension 36 that lies between the attachment portion 32 andthe second end 30. The extension 36 positions the second end 28 of thefixation member 14 away from the mouthpiece member 12. The length of theextension 36 is sufficient to position the second end 30 of the fixationmember 14 outside of a patient's mouth (not shown) when the mouthpiecemember 12 and fixation member 14 are in use. It is appreciated that theshape and length of the extension 36 may vary in accordance with thepresent disclosure.

As shown in FIG. 2, the second end 30 of the fixation member 14 isspaced-apart from the attachment portion 32 of the first end 28. Thesecond end 30 includes a plate 40 coupled to the extension 36 andfasteners 42 extending from the plate 40. Upon assembly, the fasteners42 are locked to the fastener plate 16 in order to couple the fixationmember 14 and fastener plate 16 together. Illustratively, fasteners 42are formed as two flexible arms 44 that extend away from the plate 40.Each arm 44 includes a support 49 and four teeth 46 positioned to engagethe fastener plate 16. The teeth 46 are configured with faces 48 toengage the fastener plate 16 to couple the fixation member 14 andfastener plate 16 together. The teeth 46 further include ramped surfaces54 that cooperate with the flexible arms 44 to move the arms 44 in aninward direction as shown by arrows 50 during movement of the fastener16 in a fastener-installing direction 53. It is appreciated that thefixation member 14 may include greater that two arms and said arms mayinclude a greater or fewer than four teeth in accordance with thisdisclosure. It is further appreciated that in addition to arms 44, pins,staples, clips, screws, rods, rivets, adhesives or other fasteningmechanisms may be used to couple fixation member 14 and fastener plate16 together.

As shown in FIGS. 1 and 2, the fastener plate 16 is formed for couplingwith fasteners 42. Specifically, the fastener plate 16 includes firstand second surfaces 56, 58 and apertures 60 extending between the firstand second surfaces 56, 58. Each aperture 60 is positioned in generalalignment with the arms 44. However, apertures 60 are a bit off-set fromteeth 46 such that ramped surfaces 54 of each tooth 46 engages the plate16 moving the arm 44 in direction 50 during installation of plate 16onto the fixation member 14. It is appreciated that the number ofapertures 60 may vary in accordance with the present disclosure basedupon the number of arms 44.

As shown in FIG. 2, upon assembly of fastener plate 16 onto the fixationmember 14, one face 48 of each tooth 46 engages the second surface 58 ofthe fastener plate 16. It is appreciated that the distance that thefastener plate 16 is positioned away from the plate 40 may vary inaccordance with the present disclosure. The distance may vary dependingupon the presence or absence of the spacer 18 as well as the thicknessof the mask 52, as shown in FIG. 5.

Spacer 18 is illustrated in FIGS. 1 and 2. The spacer 18 is formed of adeformable material that will allow the fastener plate 16 to be pressedtoward the plate 40. Preferably, the spacer 18 is formed of silicone,but it is appreciated that any number of deformable materials may beused in accordance with this disclosure. Spacer 18 includes oppositesurfaces 62, 64. Depending upon a variety of factors including thenumber of teeth on arms 42, apparatus 10 may not require the spacer 18to adequately couple itself to the mask 52.

Apparatus 10 is suitable for use with the mask 52 as shown in FIGS. 3-5.One of ordinary skill in the art appreciates that thermoplastic masks 52have been used for patient positioning and immobilization, in forexample physical therapy and radiation therapy for years. Such masks 52are useful for placement/positioning (using fiducials directly on thethermoplastic), as well as immobilization during scanning and treatment.It is also appreciated that once formed, the mask 52 is conventionallysupported by a frame (not shown). Such a frame may either allow for asingle patient position, or may be formed to permit the patient to beset up in a supine flat, supine tilted, lateral, or prone position.

Mask 52 is formed of thermoplastic materials that soften under heat, arecapable of being molded and shaped with hand pressure, and harden oncooling without undergoing chemical changes. A thermoplastic material,suitable for use as a mask, should soften at sufficiently lowtemperatures so as to form a pliable “mask” that can be formed to thepatient's anatomical contours without injury due to scalding or burningof the skin. Non-limiting examples of such contours are shown in FIG. 3and include the nose region 68, the chin region 70, and the foreheadregion 72. The suitable thermoplastic material should also harden as itcools to form a custom, comfortable mold for rigid fixation throughout atreatment and/or imaging process.

Suitable polymers that melt or soften at temperatures ranging from 50degree C. to 100 degree C. include poly (ethyleneadipate), poly(epsilon-caprolactone), polyvinyl stearate, cellulose acetate, butyrateand ethyl cellulose poly (propylene oxide) containing comonomers, transpolyisoprene and cis polyisoprene based thermoplastic materials, andpolycaprolactone based materials including commercially availablepolycaprolactone thermoplastic materials known as AQUAPLAST, SYNERGY,EZEFORM, POLYFORM and POLYFLEX II. These thermoplastic materials areavailable from the Rehabilitation Division of Smith & Nephew Smith &Nephew Inc., Germantown Wis.

In order to maintain a more rigid position of the mask 52 on the head ofa patient (not shown), the mouthpiece member 12, which has beenpreviously coupled to the fixation member 14, is heated to soften it andthen placed in the patients' mouth. In one aspect of the invention, themouthpiece member 12 is heated in boiling water and then placed incooler water briefly before inserting it into the patient's mouth. Oncethe mouthpiece member 12 is in the patient's mouth, the patient bitesdown on the inner surface 23 and creates a vacuum in the mouth causingthe mouthpiece member 12 to mold to the patient's dentition, or gingiva.Thus, the patient's teeth, or gingiva rest within the teeth receivingportion 22 and against the inner surface 23. Once cool, the mouthpiecemember 12 is fixed relative to the patient's maxilla and the fixationmember 14 that extends from mouthpiece member 12 will be in the samelocation relative to the patient's maxilla each time the mouthpiecemember 12 is placed in the patient's mouth.

The softened thermoplastic material of the mask 52 is placed across theface of the patient such that the thermoplastic material extends overthe fixation member 14, as shown in FIGS. 3-5. While the thermoplasticmaterial cools and hardens, the fastener plate 16 is coupled to thefasteners 42 to secure the mouthpiece member 12 to the mask 52.Following cooling, the mask 52 reflects the contours of the patient'sface, creating a mold. The apparatus 10 of the present inventiontherefore is formed to couple the mask 52 to the fixation member 14 sothat the mouthpiece member 12 is in a fixed position relative to themask 52.

FIGS. 6-8 and 13-14 illustrate an aspect of the invention in the form ofan apparatus 110 that is formed to maintain a more rigid position of themask 52 on the head of a patient (not shown). Referring now to FIG. 6,apparatus 110 includes the mouthpiece member 12, a fixation member 114extending from the mouthpiece member 12, and a fastener plate 116.

The fixation member 114 is formed of similar materials as the fixationplate 14. Fixation plate 114 is coupled to the front side 24 of themouthpiece member 12 and is formed for attachment to the fastener plate116. Referring to FIG. 6, the fixation member 114 includes a first end128 coupled to mouthpiece member 12 and a second end 130 that is formedfor attachment with the fastener plate 116. It is appreciated thatfixation member 114 may be formed in a variety of shapes and sizes inaccordance with the present invention. It is also appreciated thatalthough the fixation member 114 is illustratively formed of a rigidplastics material, it could be constructed of a variety of materialsincluding metal in accordance with the present disclosure.

The first end 128 of the fixation member 114 includes an attachmentportion 132 that takes the general shape of the mouthpiece member 12.The attachment portion 132 is coupled to mouthpiece member 12 with aresinous material that softens when heated. A non-limiting example of asuitable material for coupling the attachment portion 132 to themouthpiece member 12 is ELVAX® 470. It is appreciated that theattachment portion 132 may be coupled to the mouthpiece using a widevariety of commercially available adhesives or with welding (heat orultrasonic) in accordance with this disclosure. The first end 128 of thefixation member 114 further includes extension 36 that lies between theattachment portion 132 and the second end 130 of the fixation member114.

As shown in FIGS. 6 and 8, the second end 130 of the fixation member 114is spaced-apart from the first end 128. Referring now to FIG. 6, thesecond end 130 includes a plate 140 coupled to the extension 36 andfasteners 142 extending from the plate 140. Upon assembly, the fasteners142 are locked to the fastener plate 116 in order to couple the fixationmember 114 and fastener plate 116 together. Illustratively, fasteners142 are formed as four pins 143 and a tab 145 extending from the plate140. Each pin 143 is positioned in general alignment with a corner ofthe plate 140 and the tab 145 is centrally positioned between the pins143. It is appreciated that the size, shape, and number of pins may varyin accordance with this disclosure. In addition, while tab is shown toinclude two openings 147, the number, size, and shape of openingsthrough tab may vary in accordance with the disclosure. It is furtherappreciated that in addition to pins, rods, staples, rivets, screws,teeth, clips, adhesives or other fastening mechanisms may be used tocouple fixation member 114 and fastener plate 116 together.

Fastener plate 116 is shown in FIGS. 6 and 7. Plate 116 is formed tocorrespond with fasteners 142. Plate 116 includes four openings 144 thatare formed for alignment with pins 143 and a slot 146 sized to receivethe tab 145. As shown in FIGS. 7 and 8, upon assembly of fastener plate116 onto the fixation member 114, each pin extends through acorresponding opening 144.

Fastener plate 116 is coupled to fasteners 142. As discussed above, itis appreciated that the plate 116 can be coupled to the fixation member114 with an adhesive or by snapping on a clip (not shown) that extendsthough the openings 144 once the pins 143 and the tab 145 extend thoughopenings 144 and slot 146 of the fastener plate 116. It is appreciatedthat the distance that the fastener plate 116 is positioned from thefixation member 114 may vary in accordance with the present disclosure.The distance may vary depending upon the presence or absence of thespacer 18 as well as the thickness of the mask 52 (FIG. 8). It isfurther appreciated that the fasteners may be alternatively formed onplate, and apertures and slot may be formed in fixation member 114 inaccordance with this disclosure.

Apparatus 110 is suitable for use with the mask 52 as shown in FIGS. 7and 8. The mouthpiece member 12 that is coupled to the fixation member114 is softened and inserted into a patient's mouth as described abovewith reference to apparatus 10. The softened thermoplastic material ofthe mask 52 is then placed across the face of the patient such that thethermoplastic material extends over the fixation member 114. Duringcooling of the mask 52, the fastener plate 116 is coupled to thefasteners 142 to secure the mouthpiece member 12 to the mask 52.Following cooling and hardening of the mask 52, the mask 52 is formed tothe contours of the patient's face, creating a mold as previouslydescribed. Apparatus 110 of the present invention therefore provides isfixed relative to the head of the patient each time the hardened mask 52is applied to the patient.

In another aspect of the invention, an apparatus 210 is provided that isformed to couple the thermoplastic mask 52 to the internal auditorycanal of the patient. As shown in FIGS. 9 and 11, apparatus 210 includesan earplug member 214, a fastener plate 216, and spacers 218. Earplugmember 214 is formed from a commercially available tissue non-equivalentmaterial, a non-limiting example of which includes carbon fiber. Theearplug member 214 includes an earplug 220 that extends from plate 40.The earplug 220 is generally conical in shape and includes a first end222 and a second end 224 positioned at the plate 40. It is appreciatedthat the earplug 220 may take on a variety of shapes and sizes inaccordance with this disclosure. Fasteners 42 extend from plate 40 awayfrom the earplug 220.

Fastener plate 216 is formed of materials similar to fastener plate 16.Plate 216 includes a first surface 256 facing the earplug member 214 andan opposite second surface 258. In addition, apertures 260 extendbetween the first and second surfaces 256, 258. It is appreciated, thatapertures 260 will be aligned with fasteners 42 as discussed above withreference to apparatus 10. Additionally, it is appreciated that ratherthan fasteners 42, pins, rods, staples, rivets, screws, teeth, clips,adhesives or other fastening mechanisms may be used to couple fastenerplate 216 and earplug member 214 together.

Spacers 218 are each formed of materials similar to spacer 18. Spacers218 each include first and second surfaces 262, 264. In addition,apertures 266 extend between the first and second surfaces 262, 264. Itis appreciated, that apertures 266 will be aligned with apertures 260 asdiscussed above with reference to apparatus 10.

In order to maintain a more rigid position of the mask 52 on the head ofa patient (not shown), the earplug member 214 is placed in the auditorycanal of a patient's ear. Once positioned, the plate 40 that lies at theend 224 of the earplug 220 will be in the same location relative to thepatient's auditory canal (not shown) each time the earplug 220 is placedin the patient's ear. A spacer 218 is placed on the plate 40 so that thefasteners 42 extend through the apertures 266.

The softened thermoplastic material of the mask 52 is placed across theface of the patient such that the thermoplastic material extends overthe spacer 218 that lies on the plate 40 of the earplug member 214. See,FIG. 11. As the thermoplastic material cools, the second spacer 218 isplaced on the mask 52, followed by the fastener plate 216 so that thefasteners 42 extend through apertures 266, 260 respectively. Thefastener plate 216 is coupled to the fasteners 42 to secure the earplugmember 214 to the mask 52. Once the thermoplastic material has cooledand hardened, the mask is formed to the contours of the patient's face,creating a mold. Apparatus 210 of the present invention therefore fixesthe thermoplastic mask relative to the auditory canal of a patient,preventing movement of the patient's head in the mask 52.

In another aspect of the invention, an apparatus 310 is provided that isformed to couple the thermoplastic mask 52 to the nasal bridge of apatient. Apparatus 310 is shown in FIGS. 10, 11, 13, and 14 and includesa nose block 320, a fixation member 314 formed to be coupled to the noseblock 320, a fastener plate 316, and a spacer 318. Nose block 320 isformed from a commercially available resinous material that softens whenheated. A non-limiting example of a suitable material for forming thenose block 320 is ELVAX® 470, an ethylene vinyl acetate copolymer andterpolymer resin, which is commercially available from E.I. DuPont deNemours, Wilmington, Del. It is appreciated, however that the nose block320 can also be a true custom mould in accordance with this disclosure.The nose block 320 is illustratively a block of material that includes afront face 336, a rear face 338, and sides 340 that extend between thefront and rear faces 336, 338. It is appreciated that the nose block 320may take on a variety of shapes and sizes in accordance with thisdisclosure.

Fixation member 314 includes plate 40, an attachment portion 332extending from the plate 40, and fasteners 42 extending from the plate40 away from the attachment portion 332. The fixation member 314 isformed of materials similar to fixation member 14, as previouslydescribed. Attachment portion 332 of fixation member 314 includesconnectors 334 that extend generally perpendicular from arms of portion332. The connectors 334 are coupled to the nose block 320 usingultrasonic welding. It is appreciated, however, that the attachmentportion 332 of the fixation member 314 may be coupled to the nose block320 using any number of commercially available adhesives or with heatwelding in accordance with this disclosure.

Fastener plate 316 is formed of materials similar to fastener plate 16.Plate 316 includes apertures 360 that are positioned so that they willbe aligned with fasteners 42 as discussed above with reference toapparatus 10, upon assembly of apparatus 310. Further, it is appreciatedthat rather than fasteners 42, plate 316 and the fixation member 314 maybe coupled together using pins, rods, staples, rivets, screws, teeth,clips, adhesives or other fastening mechanisms in accordance with thepresent disclosure. Spacer 318 is formed of materials similar to spacer18. Spacer 318 includes apertures 366 that will be aligned withapertures 360 when apparatus 310 is assembled.

In order to maintain a more rigid position of the mask 52 on the head ofa patient (not shown), the nose block 320, which is coupled to fixationmember 314, is heated to soften the nose block 320. The nose block 320is then pressed on the nasal bridge of the patient to create a mold ofthe nasal bridge (not shown). In one aspect of the invention, the noseblock 320 is heated in boiling water and then placed in cooler waterbriefly before placing it on the patient's nose. Once cool, the shape ofthe nose block 320 is fixed and the fixation member 314 that extendsfrom nose block 320 will be in the same location relative to thepatient's nasal bridge each time the nose block 320 is placed on thatnasal bridge.

Once the nose block 320 is cool, the softened thermoplastic material ofthe mask 52 is placed across the face of the patient such that thethermoplastic material extends over the fixation member 314 that iscoupled to the nose block 320. See, FIGS. 11, 13, and 14. During coolingof the thermoplastic material, the spacer 318 is placed on the mask 52,followed by the fastener plate 316 so that the fasteners 42 extendthrough apertures 366, 360 respectively. The fastener plate 316 iscoupled to the fasteners 42 to secure the nose block 320 to the mask 52.Once the thermoplastic material has cooled and hardened, the mask 52 isformed to the contours of the patient's face, creating a mold. Theapparatus 310 of the present invention therefore fixes the thermoplasticmask relative to the nasal bridge of a patient, preventing movement ofthe patient's head in the mask 52.

In another aspect of the invention, an apparatus 410 is provided that isformed to couple the thermoplastic mask 52 to the internal auditorycanal of the patient. As shown in FIGS. 12-14, apparatus 410 includes anearplug member 414 and a fastener plate 416. Earplug member 414 isformed from a commercially available tissue non-equivalent material, anon-limiting example of which includes carbon fiber. The earplug member414 includes the earplug 220 that extends from a plate 440. The plateincludes four apertures 442.

Fastener plate 416 is formed of materials similar to fastener plate 16.Plate 416 includes four posts 443. The posts 443 are positioned foralignment with apertures 442. It is appreciated that the number andlocations of posts can vary in accordance with the present disclosure solong as they are in alignment with the apertures 442. Further, it isappreciated that rather than posts 443, the fastener plate 416 and theearplug member 414 may be coupled together using pins, rods, staples,rivets, screws, teeth, clips, adhesives or other fastening mechanisms inaccordance with the present disclosure.

In order to maintain a more rigid position of the mask 52 on the head ofa patient (not shown), the earplug 220 is placed in the auditory canalof a patient's ear. Once positioned, the plate 440 that lies at that end224 of the earplug 220 will be in the same location relative to thepatient's auditory canal each time the earplug 220 is placed in thepatient's ear.

The softened thermoplastic material of the mask 52 is placed across theface of the patient such that the thermoplastic material extends overthe plate 440. See, FIGS. 13 and 14. As the thermoplastic materialcools, the fastener plate 416 is placed on the mask 52 so that the pins443 extend through apertures 442. The fastener plate 416 is coupled tothe pins 443 to secure the earplug member 414 to the mask 52. It isappreciated that the fastener plate 416 may be coupled to plate 440using a variety of adhesives, fasteners, etc. Once the thermoplasticmaterial has cooled and hardened, the mask 52 is formed to the contoursof the patient's face, creating a mold. Apparatus 410 of the presentinvention therefore fixes the thermoplastic mask relative to theauditory canal of a patient, preventing movement of the patient's headin the mask 52.

As shown in FIGS. 11, 13, and 14 it is appreciated that one or acombination of more than one apparatus 10, 110, 210, 310, 410 may beused to fix the thermoplastic mask relative to the patient's head inaccordance with this disclosure.

FIG. 15 illustrates aspects of the invention in the form of assembly 510that includes a mask that is formed to be fixed relative to craniofacial bones, i.e. maxilla. Assembly 510 includes mouthpiece member 12that is fixed to the mask 52 with an adhesive. Suitable adhesives areresinous materials that soften when heated. A non-limiting example of asuitable adhesive material is ELVAX® 470, an ethylene vinyl acetatecopolymer and terpolymer resin, which is commercially available fromE.I. DuPont de Nemours, Wilmington, Del. It is appreciated, however thatthe adhesive may be selected of any number of commercially availableadhesives. In addition, it is appreciated that pins, rods, staples,rivets, screws, teeth, clips, or any number of fastening mechanisms maybe used to couple the mouthpiece member 12 and mask 52 together inaccordance with the present disclosure.

In order to maintain a more rigid position of the mask 52 relative tothe maxilla, the mouthpiece member 12 is heated to soften it and thenplaced in the patients' mouth. In one aspect of the invention, themouthpiece member 12 is heated in boiling water and then placed incooler water briefly before inserting it into the patient's mouth. Oncethe mouthpiece member 12 is in the patient's mouth, the patient bitesdown on the inner surface 23 and creates a vacuum in the mouth causingthe mouthpiece member 12 to mold to the patient's dentition, or gingiva.Thus, the patient's teeth, or gingiva rest within the teeth receivingportion 22 and against the inner surface 23.

The softened thermoplastic material of the mask 52 is placed across theface of the patient such that the thermoplastic material extends overthe warm front side 24 of the mouthpiece member 12. While thethermoplastic material cools and hardens, the warm adhesive is appliedto the front side 24 and mask 52 to secure the mouthpiece member 12 tothe mask 52. Following cooling, the mask 52 reflects the contours of thepatient's face, creating a mold. The assembly 510 of the presentinvention therefore fixes the thermoplastic mask relative to the maxillaof a patient, preventing movement of the patient's head in the mask 52.

In addition, as illustrated in FIGS. 16 and 17 respectively, it isappreciated that nose block 320 and earplug 222 may be coupled directlyto mask 52 in a manner similar to mouthpiece member 12 as describedabove with reference to assembly 510 to form assemblies 610, 710. It isfurther appreciated that pins, rods, staples, rivets, screws, teeth,clips, or any number of fastening mechanisms may be used to couple thenose block 320 and earplug 222 to their respective mask 52 in accordancewith the present disclosure.

FIGS. 18-19 illustrate aspects of the invention in the form of assembly810 that includes a mask that is formed to be fixed relative to craniofacial bones, i.e. maxilla. Assembly 810 includes the mouthpiece member12, the fixation member 14 extending from the mouthpiece member 12, thefastener plate 16, and a lower plate member 812.

Illustratively, the lower plate member 812 is coupled to the fastenerplate 16 and has a tongue block plate 814 that extends adjacent to themember 12. The tongue block plate 814 serves to restrict movement of thepatient's tongue past the mouthpiece member toward the patient's upperpalate (not shown).

Lower plate member 812 is illustratively is coupled to the fixationmember 14. Referring to FIG. 19, the lower plate member 812 is generallyformed from a rigid plastics material and includes a tab 816 coupled tothe fixation member 14 and the tongue block plate 814 is positionedadjacent to the bottom side 25 of the member 12. Lower plate member 812may be formed in a variety of shapes and sizes in accordance with thepresent invention. It is also appreciated that although the lower platemember is illustratively formed of a rigid plastics material, it couldbe constructed of a variety of materials in accordance with the presentdisclosure.

As shown in FIG. 19, the tab illustratively includes a front face 818, arear face 820, and top and bottom edges 822, 824 extending between thefront and rear faces 818, 820. Referring now to FIG. 18, slots 826, 828extend from the top edge 822 through a portion of the tab 816. The slots826, 828 are in general alignment with the fasteners 42 of the fastenerplate 16. As such, once the apparatus 810 is assembled, the arms 44extend through the respective slots 826, 828 and the rear face 820 iscoupled to the plate 40. It is appreciated that while two open-endedslots are illustrated, the size, shape, and location of the slots mayvary depending upon the size shape and location of fasteners 42.Further, it is appreciated that the slots may not be necessary dependingupon the shape and size of the tab in accordance with the presentinvention.

Illustratively, the rear face 820 of tab 614 is coupled to the fastener14 using any one of a wide variety of commercially available adhesivesstrong enough to hold face 820 and tab 614 together. In addition, it isappreciated that pins, rods, staples, rivets, screws, teeth, clips,ultrasonic welding, heat welding, or any number of fastening mechanismsmay be used to couple the lower plate member 812 and fixation member 14together in accordance with the present disclosure.

Referring now to FIG. 19, an extension 886 lays between the tab 816 andthe tongue block plate 814. The length of the extension 886 issufficient to position tongue block plate 814 adjacent to the bottomside 25 of the member 12. Extension 886 includes a dip portion 888 sizedto receive a portion of the fastener 14 therein. It is appreciated thatthe shape and length of the extension 886 may vary in accordance withthe present disclosure.

As shown in FIG. 19, the tongue block plate 814 is spaced-apart from thetab 816. The tongue block plate 814 includes forward end 828 coupled tothe extension 886, an opposite rearward end 830, an upper surface 832facing the bottom side 25 of member 12, and a lower surface 836 facingthe patient's tongue (not shown) during use. Referring to FIG. 18, thetongue block plate 814 extends across the cavity 27 of the member 12 inorder to block movement of the tongue therein. The plate 814 has aheight of about ⅛ inch, however it is appreciated that the height of theplate 814 may vary in accordance with the present invention.

The tongue block plate 814 is further formed to include a channel 834extending between the forward and rearward ends. The channel is sized topermit movement of patient directed air therein. Illustratively, thechannel is about 1/16 inch in height; however, it is appreciated thatthe height of the channel may vary in accordance with the presentinvention. It is further appreciated that in another aspect of theinvention, the plate 814 may be formed without a channel.

Upon assembly of lower plate member 812 onto the fixation member 14, therear face 820 of tab 816 is coupled to the plate 40 and the plate 814 ispositioned adjacent to bottom side 25 of the member 12 such that theplate 616 at least substantially blocks the cavity 27. It is appreciatedthat the distance the tongue of the patient is kept away from the member12 and hence the upper palate is dependent upon the height of the plate814. As such, it is appreciated that the height of the plate 814 mayvary in accordance with the present invention.

Having described the invention in detail and by reference to specificembodiments thereof, it will be apparent that modification andvariations are possible without departing from the scope of theinvention defined in the appended claims. More specifically, althoughsome aspects of the present invention are identified herein, it iscontemplated that the present invention is not necessarily limed tothese one aspects of the invention.

1: An apparatus formed to fix a thermoplastic mask to a patient, theapparatus comprising: a member having a teeth-receiving portion formedto be positioned adjacent to a cranio facial bone of the patient, afixation member coupled to the member, the fixation member including aplate and a fastener, a distinct fastener plate formed for coupling withthe fastener to couple the mask to the fixation member so that themember is in a fixed position relative to the mask, and a lower platemember positioned adjacent to the member. 2: The apparatus of claim 1wherein the lower plate member includes a tongue block plate formed witha channel therein. 3: The apparatus of claim 2 wherein the lower platemember includes a tab coupled to the fixation member. 4: The apparatusof claim 1 wherein the member includes a top side and a bottom side andthe lower plate member includes a tongue block plate positioned adjacentto the bottom side. 5: The apparatus of claim 1 wherein the lower platemember is coupled to the fixation member. 6: The apparatus of claim 5wherein the lower plate member includes a tab coupled to the plate. 7:The apparatus of claim 6 wherein the tab is coupled to the plate with anadhesive. 8: An apparatus formed to fix a thermoplastic mask to apatient, the apparatus comprising: a mouthpiece member, a fixationmember coupled to the mouthpiece member, the fixation member including aplate and at least one fastener extending away from the plate, adistinct fastener plate formed for attachment with the at least onefastener so that the mask is coupled between the plate and the fastenerplate, and a lower plate member positioned adjacent to the mouthpiecemember. 9: The apparatus of claim 8 wherein the lower plate memberincludes a tab and a tongue block plate spaced-apart from the tab. 10:The apparatus of claim 9 wherein the tongue block plate includes achannel therein. 11: The apparatus of claim 8 wherein the lower platemember includes a tab formed with at least one slot sized to receive theat least one fastener therein. 12: The apparatus of claim 9 wherein thetab is coupled to the plate with an adhesive. 13: The apparatus of claim8 wherein the lower plate member is formed to include a channel therein.14: An assembly formed to immobilize a patient's skull during a medicalprocedure, the assembly comprising: a thermoplastic mask, a fixationmember including an attachment portion, an extension extending from theattachment portion, and a plate coupled to the extension, the mask beingformed to extend across the plate, a mouthpiece member coupled to theattachment portion of the fixation member in order that the mouthpiecemember be coupled to the thermoplastic mask, and a lower plate memberpositioned adjacent to the mouthpiece member. 15: The apparatus of claim14 wherein the lower plate member includes a tab coupled to the plate.16: The apparatus of claim 15 wherein the tab is coupled to the platewith an adhesive. 17: The apparatus of claim 14 wherein the lower platemember includes a tongue block plate formed with a channel therein. 18:The apparatus of claim 17 wherein the lower plate member includes a tabcoupled to the fixation member. 19: The apparatus of claim 18 whereinthe lower plate member includes an extension extending between the taband the tongue block plate. 20: The apparatus of claim 14 wherein themouthpiece includes a top side and a bottom side and the lower platemember includes a tongue block plate positioned adjacent to the bottomside.